Intermittent driving mechanism



Aug. 17, 1954 A. LEECH INTERMI'ITENT DRIVING MECHANISM 6 Sheets-Sheet 1 Filed Sept. 8, 1949 L. A. LEECH INTERMITTENT DRIVING MECHANISM Aug. 17, 1954 6 Sheets-Sheet 2 Filed Sept. 8. 1949 I a ar j 042mg Aug. 17, 1954 A. LEECH INTERMITTENT DRIVING MECHANISM 6 Sheets-Sheet 3 Filed Sept. 8. 1949 Aug. 17, 1954 A. LEECH INTERMITTENT DRIVING MECHANISM 6 Sheets-Sheet 4 Filed Sept. 8. 1949 .Z :aMean-1'0!" lam-nee 04:22). Leeelu 3g M dz-Zane 195.4 L. A. LEECH Y 2,686,430

INTERMITTENT DRIVING MECHANISM Filed Sept. 8. 1949 s Sheets-Sheet 5 Inzrenlw lazirenne c141 cxlldneg Patented Aug. 17, 1954 INTERMITTENT DRIVING MECHANISM Laurence Arthur Leech, Bishops Stortford, England, assignor to Millars Machinery Company Limited, Bishops Stortford, England Application September 8, 1949, Serial No. 114,506

Claims priority application Great Britain September 27, 1948 Claims. (Cl. 74-124) This invention relates to belt and like conveyors such as the conveyors of belt feed hoppers in which the hopper delivers material to an endless belt forming the bottom of the hopper which belt is intermittently driven and which is adapted to deliver the material at a regular and uniform rate for example to a feed elevator or conveyor means.

Hitherto it has been the practice to drive the head drum of the belt by pawl and ratchet means located at the side of the belt, the motion of the pawl being taken from a crank actuated by a transverse shaft.

There are numerous disadvantages of such disposition of the drive. Thus in order to increase the capacity, the belt could be driven by opposed cranks but such would necessitate a duplication of the connecting rods and ratchet drive. Moreover, in order that the belt may be readily and quickly changed, the mounting of the feeder unit (belt and associated drums) could be arranged for sidewise hinging instead of an endwise move ment, but such is not altogether convenient with the side ratchet drive.

An object of the present invention is to provide an improved feeder belt drive whereby the above disadvantages are avoided.

The invention consists in the provision within the head or driving drum of a conveyor of an 05-- cillatable one-way drive means actuated by a shaft upon which the drum freely turns whereby an intermittent drive is imparted to the drum.

According to the invention the head or driving drum of a belt conveyor is driven intermittently by ratchet mechanism enclosed within the drum and actuated by rotary cam means located within the drum.

The drum may be freely rotatable upon the cam shaft and have an internal ratchet wheel secured to its inner surface with which an oscillating pawl actuated by the cam engages.

Adjustable stop means may be provided for controlling the stroke of the pawl and amplitude of movement of the drum.

In the accompanying drawings:

Figure 1 is an end view of the driving drum of a belt conveyor with the invention applied, the parts being in a no-drive position;

Figure 2 is a similar view with the parts in a position to provide an intermittent movement to the drum;

Figure 3 is a section (on an enlarged scale) taken on line 33 of Figure 2;

Figure 4. is a plan of Figure 3;

Figure 5 is a side elevation showing the sup- 2 porting framework for the belt conveyor and head and tail drums;

Figure 6 is a plan corresponding to Figure 5;

Figure 7 is an end view showing the supporting means by which the drums and belt are displaceable to permit removal of the belt conveyor;

Figure 8 is a sectional elevation showing a double drive for the drum and the mode of dividing the driving shaft;

Figure 9 is a half section showing a modified arrangement of double drive in which a solid shaft is employed.

In carrying the invention into effect according to one convenient mode by way of example in the application of the invention to a belt feed hopper, the head or driving drum I (see Figures 1 to 4) is mounted to rotate freely upon a horizontal cam shaft 2 to which a drive is imparted by any suitable gearing, for example, chain gear through sprocket wheel 3.

The drum I towards one end is provided with an internal ratchet gear 4 having a number of teeth adapted to give even wearing properties with a driving pawl. lhe ratchet A may be formed in any suitable manner as a ring and secured to the drum I.

The adjacent end of the drum l is closed by a stationary disc or end plate 5 which is rigidly secured to a suitable part of the framing l5 of the machine or belt conveyor unit. The end plate 5 forms a support for a carrier unit 6 which is bolted or otherwise secured thereto.

The carrier unit 6 extends parallel to the axis of the drum and has pivotally mounted upon one end thereof, a pair of curved arms 1 which extend over the cam shaft 2. The arms 1 are spaced apart and support between them a cam roller 8 which is adapted to engage the cam 9 on the shaft 2 whereby the arms 1 are oscillated.

Depending freely from the cam shaft 2 is a pair of radial swinging arms Hi. The ends of these arms l0 and the fre ends of the curved arms 1 are connected by a pair of links H. The swing ing arms ill also carry a pin 12 upon which a pawl I3 is pivotally mounted, the pawl lying between the links H. The pawl falls by gravity or is biassed by suitable spring means into engagement with the ratchet teeth 4 at the lower zone of the drum I.

In operation as the cam shaft 2 rotates, the cam 9 raises the curved arms 1 causing the swinging arms H! to turn about the axis of the shaft 2 and through the pawl l3 impart movement to the drum I. As the cam roll 8 runs down the cam 9 the curved arms are lowered by gravity and the pawl l3 rides over the ratchet teeth 4. Thus an intermittent feeding movement is imparted to the drum l and endless band conveyor [4 driven thereby.

Instead of a single lobe cam, one having two or more lobes maybe provided to give a multiple driving effect for one revolution of the cam shaft 2.

The amplitude of the intermittent movement of the drum i may be varied by controlling the return movement of the pawl i3. Thus an adjustable stop 16 may be provided on a fixed part of the framing IS with which a lever 11 attached to a spindle [8 associated with the pivotal end of the curved arms 1 co-operates, the arrangement being such that by an adjustment of the stop It, the arms 7 and associated pawl I3 is limited in the return movement whereby the forward movement by the action of the cam 9 is varied, to say the pitch space of one, two or three ratchet teeth or other convenient number of teeth.

By an appropriate adjustment of the stop l6 the cam roller 8 may be raised to a position in which it is out of the operative path of the cam 9 (see Figure 1) so that no drive will be imparted to the conveyor band M.

The stop I6 is mounted to slide in a bearing tube I 13 which engages the lever ll. A pin 20 on the stop 56 engages in a helical slot 2| in the tube H8, and is adapted to seat in recesses in the tube and to be held therein by a spring l9.

The arrangement of the drive means within the drum provides a neat and compact apparatus in which only simple guard means for the shaft drive are required. Moreover by the elimination of the laterally disposed crank and pawl and ratchet drive the feeder unit may be hinged sidewise to facilitate belt changing.

The conveyor band [4 (Figures 5, 6 and '7) which forms the bottom of a hopper 22 is mounted upon the head or driving drum and an adjustable drum 23, its upper lap Ma being supported by a series of rollers 24. The hopper is provided with an adjustable gate valve 221: and side plates 221) which overlie the conveyor band.

The bearings 25 for the shaft 2, the adjustable bearing 26 for the drum 23, and the spindles I25 of the roller 24 are supported by a framing l comprising pairs of side angles 21 connected together by plates 28 and angles 29. To the lower angles 21 transverse supporting hinge channels 30 are connected. The upper angles 27 have secured thereto supporting lugs 3 I, 3 la. The hinge channels '30 extend to one side of the conveyor unit and are hinged at 32 to a part 33 of the hopper supporting frame 34.

Each supporting lug 3! is adapted to be removably connected by a link 35 to the frame 34, the arrangement being such that when in the operative position the conveyor unit is supported by the hinge channels 3!] and the lugs 3!.

The other lugs 31a are connected by double links 36 to the frame 34 which links when the unit is in operative position will carry no weight. When it is desired to remove or replace the conveyor band 14, the connection between the lugs 31 and links 35 are removed so that the weight of the unit will be taken by links 36 the parts then taking the position shown in dot and dash lines in Figure 'lin which the links 36 are aligned.

The ratchet mechanism may be duplicated at the other end of the head drum, and in such case for wide feeder units the two cams may be relatively located to transmit an equal torque to the drum, but for large output the cams could be opposed or set at any suitable angle to each other so as to provide a long continuous movement or two movements per revolution of the cam shaft depending upon the nature of the material to be handled by the feeder unit.

Referring to Figure 8 the drum 3'! is provided with two ratchet drive mechanisms each of similar construction to that shown in Figure 3 and indicated generally by the reference 38. The

ratchet drive mechanisms are located between the fixed plates 39 and inner plates 40 secured to the drum and on which bearings 41 are provided for the cam shaft 42. In order to facilitate assembly, the shaft '42 is divided and formed with halved joint ends 43 which are coupled by a sleeve M and coupling pin 45 insertible through a hole 46 in the drum shell. The divided shaft may have a tongue and groove connection.

As an alternative a. solid shaft 41, Figure 9, may be used upon which the various parts of the ratchet gear and other parts of the mechanism are assembled after which the drum shell 48 is mounted in position and secured by screws 49. The ratchet gear and other parts associated therewith are similar to those described above.

With the duplicate drive as shown in Figure 8 when used for relative wide feeder units the cams 5Q, 51 may be relatively located to transmit an equal torque to the drum. For large output the cams could be opposed or set at any other suitable angle to each other so as to provide along continuous movement of the conveyor or two stepping movements per revolution of the cam shaft depending upon the nature of the material to be handled by the feeder unit.

I claim:

1. Intermittent driving mechanism comprising in combination a driving shaft, a drum freely rotatable on said driving shaft, said drum forming a terminal element of an endless belt, an internal ratchet gear mounted on the interior surface of the drum, a pawl located within the drum and engaging the ratchet gear, a radius "arm located within the drum and on which the pawl is pivotally mounted, said arm being freely mounted on said shaft, cam means on said driving shaft operative to impart a driving stroke to the pawl to intermittently rotate the drum.

2. Intermittent driving mechanism as claimed in claim 1, wherein a stationary mounting plate is located adjacent one end of said drum, a curved arm pivctally mounted on said stationary mounting plate and having a free end, a cam roller mounted on said arm and engaging said cam means, and a link connecting the free end of said arm and the radius arm.

3. Intermittent driving mechanism as claimed in claim 2, wherein a lever is mounted on the curved arm and is movable therewith, an adjustable stop lying in the path of said lever, whereby the return movement of the pawl may be adjusted to adjust the amplitude of the intermittent movement of the drum.

4. Intermittent driving mechanism as claimed in claim 3, wherein said stop is adjustable to a position in which said curved arm occupies a no-drive position.

5. Intermittent driving mechanism comprising a, driving shaft, a drum freely rotatable on said shaft, an internal ratchet gear mounted on the interior surface of the drum adjacent one end thereof, a second internal ratchet gear mounted on the interior surface of the drum adjacent the other end thereof, a. driving pawl for each of said gears, said pawls being pivotally mounted on radius arms freely mounted on the shaft, a pair of cams on said shaft, one cam being operative to impart a driving stroke to one pawl, the other cam being operative to impart a driving stroke to the other pawl, whereby the drum is intermittently rotated.

References Cited in the file of this patent Number Number Name Date Michaud Sept. 22, 1909 Skublin Sept. 12, 1916 Hawson Feb. 12, 1929 Talley May 2, 1933 Bridges Feb. 6, 1934 Bassett July 23, 1940 Nebuda Mar. 4, 1941 FOREIGN PATENTS Country Date Germany Sept. 9, 1922 France Mar. 26, 1935 

